soundlib/Snd_fx.cpp in OpenMPT before 1.27.07.00 and libopenmpt before 0.3.8 allows remote attackers to cause a denial of service (out-of-bounds read) via an IT or MO3 file with many nested pattern loops.
https://openmpt.org/openmpt-1-27-07-00-released
https://github.com/OpenMPT/openmpt/commit/7ebf02af2e90f03e0dbd0e18b8b3164f372fb97c